Aircraft

ABSTRACT

An aircraft includes: a plurality of rotor units each including a propeller and a motor that drives the propeller; a balloon that laterally covers the plurality of rotor units, across the height of the plurality of rotor units in the up-and-down direction; a camera that protrudes, along a predetermined axis, beyond the balloon; and a holding component that holds the camera and whose overall length can be shortened along the predetermined axis.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. continuation application of PCT InternationalPatent Application Number PCT/JP2017/005207 filed on Feb. 14, 2017,claiming the benefit of priority of Japanese Patent. Application Number2016-047673 filed on Mar. 10, 2016, the entire contents of which arehereby incorporated by reference.

BACKGROUND 1. Technical Field

The present disclosure relates to an aircraft including a plurality ofrotor units.

2. Description of the Related Art

Japanese Unexamined Patent Application Publication No. 2011-046355discloses an aircraft including a plurality of rotor units that eachinclude a propeller. This type of aircraft is referred to as, forexample, a multicopter or drone.

Japanese Unexamined Patent Application Publication No. H04-022386discloses an aircraft including: a single rotor unit including apropeller; and a buoyant body filled with helium gas. In the aircraftdisclosed in Japanese Unexamined Patent Application Publication No.H04-022386, the donut-shaped buoyant body is disposed so as to surroundthe surrounding area of the single rotor unit.

SUMMARY

In the aircraft disclosed in Japanese Unexamined Patent ApplicationPublication No. 2011-046355, the plurality of rotor units and thefuselage, which is equipped with on-board devices such as a camera, areexposed. The aircraft disclosed in Japanese Unexamined Patent.Application Publication No. H04-022386 achieves flight with a singlerotor unit including a large propeller. The aircraft therefore includes,protruding beyond the buoyant body, legs for supporting the weight ofrotor unit when landing and fins for controlling flight direction.Accordingly, if either of these aircrafts experience an unexpectedflight situation, descend and contact an object, the object contacted bythe aircraft may be damaged and the on-board devices in the aircraft maybe damaged.

The present disclosure has been conceived in view of the above points,and provides an aircraft that achieves flight via a plurality of rotorunits and has improved safety.

An aircraft according to the present disclosure includes: a plurality ofrotor units each including a propeller and a motor that drives thepropeller; a shock absorber that laterally covers the plurality of rotorunits, across the height of the plurality of rotor units in theup-and-down direction; an on-board device that protrudes, along apredetermined axis, beyond the shock absorber; and a holding componentthat holds the on-board device and whose overall length can be shortenedalong the predetermined axis.

With the aircraft according to the present disclosure, it is possible tocause an aircraft that contains gas that is less dense than air toquickly descend when the aircraft becomes uncontrollable.

BRIEF DESCRIPTION OF DRAWINGS

These and other objects, advantages and features of the disclosure willbecome apparent from the following description thereof taken inconjunction with the accompanying drawings that illustrate a specificembodiment of the present disclosure.

FIG. 1 is a perspective view of an aircraft according to Embodiment 1from below;

FIG. 2 is a plan view of the aircraft according to Embodiment 1;

FIG. 3 is a cross-sectional view of the aircraft taken at line III-IIIin FIG. 2;

FIG. 4 is a cross-sectional view of the aircraft taken at line IV-IV inFIG. 2;

FIG. 5 is a plan view of the balloon according to Embodiment 1;

FIG. 6 is a cross-sectional view of the balloon taken at line VI-VI inFIG. 5;

FIG. 7 is a block diagram illustrating a configuration of the aircraftaccording to Embodiment 1;

FIG. 8A is a flow chart of one example of gas release control in theaircraft according to Embodiment 1;

FIG. 8B is a flow chart of another example of the gas release control inthe aircraft according to Embodiment 1;

FIG. 9 illustrates the aircraft according to Embodiment 1 when the gasrelease control is performed;

FIG. 10 illustrates an aircraft according to Variation 1 of Embodiment 1when the gas release control is performed;

FIG. 11 illustrates an aircraft according to Variation 2 of Embodiment 1when the gas release control is performed;

FIG. 12 illustrates the aircraft according to Embodiment 1 having fallento the ground as a result of the gas release control being performed;

FIG. 13 is an enlarged view of holding components and camera in theaircraft;

FIG. 14 is an enlarged view of holding components and camera in anaircraft according to Variation 1 of Embodiment 2;

FIG. 15 is a block diagram illustrating a configuration of an aircraftaccording to Variation 2 of Embodiment 2;

FIG. 16A is a flow chart of one example of contraction control for theholding components in the aircraft according to Variation 2 ofEmbodiment 2;

FIG. 16B is a flow chart of one example of the contraction control forthe holding components in the aircraft according to Variation 2 ofEmbodiment 2;

FIG. 17 is an enlarged view of the holding components and camera in theaircraft;

FIG. 18 is an enlarged view of the holding components and camera in theaircraft;

FIG. 19 illustrates an aircraft according to Embodiment 3 when theshape-change control is performed;

FIG. 20 is a block diagram illustrating a configuration of the aircraftaccording to Embodiment 3;

FIG. 21A is a flow chart of one example of the shape-change controlperformed by the drive unit in the aircraft according to Embodiment 3;

FIG. 21B is a flow chart of another example of the shape-change controlperformed by the drive unit in the aircraft according to Embodiment 3:

FIG. 22 illustrates an aircraft according to Variation 1 of Embodiment 3when the shape-change control is performed;

FIG. 23 illustrates an aircraft according to Variation 2 of Embodiment 3when the shape-change control is performed;

FIG. 24 illustrates an aircraft according to Variation 3 of Embodiment 3when the shape-change control is performed; and

FIG. 25 illustrates an aircraft according to Variation 4 of Embodiment 3when the shape-change control is performed.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments will be described in detail with reference tothe drawings when appropriate. However, unnecessarily detaileddescription may be omitted. For example, detailed descriptions ofwell-known matters or descriptions of components that are substantiallythe same as components described previous thereto may be omitted. Thisis to avoid unnecessary redundancy and provide easy-to-read descriptionsfor those skilled in the art.

Note that the accompanying drawings and subsequent description areprovided by the inventors to facilitate sufficient understanding of thepresent disclosure by those skilled in the art, and are thus notintended to limit the scope of the subject matter recited in the claims.

Embodiment 1

(Outline of Aircraft Configuration)

Next, aircraft 10 according to Embodiment 1 will be described.

FIG. 1 is a perspective view of an aircraft according to Embodiment 1from below. FIG. 2 is a plan view of the aircraft according toEmbodiment 1. FIG. 3 is a cross-sectional view of the aircraft taken atline Ill-III in FIG. 2. FIG. 4 is a cross-sectional view of the aircrafttaken at line IV-IV in FIG. 2.

As illustrated in FIG. 1 and FIG. 2, aircraft 10 according to thisembodiment includes balloon 20 as a shock absorber, four rotor units 30,and fixing component 50. Aircraft 10 further includes release unit 26that is disposed on the upper part of first shock absorber 20 a ofballoon 20 and releases a first gas contained in balloon 20 at apredetermined timing.

As illustrated in FIG. 3 and FIG. 4, aircraft 10 is provided with, ason-board devices, controller 41, battery 42, projector 43, and camera44. Aircraft 10 is further provided with light emitter 46 (a lightingapparatus).

(Balloon)

Next, balloon 20 will be described.

FIG. 5 is a plan view of the balloon according to Embodiment 1. FIG. 6is a cross-sectional view of the balloon taken at line VI-VI in FIG. 5.

As illustrated in FIG. 3, FIG. 4, and FIG. 6, balloon 20 is made of aflexible sheet material (for example, vinyl chloride), and includes gaschamber 21, which is a space enclosed by the sheet material. In FIG. 3,FIG. 4, and FIG. 6, the bold lines indicate the cross section of thesheet material that forms balloon 20. The sheet material that forms theouter surface of balloon 20 is white in color and semitransparent so asto allow light to pass through.

Gas chamber 21 includes first gas chamber 21 a in the upper portion ofaircraft 10 and second gas chamber 21 b in the lower portion of aircraft10. Stated differently, balloon 20 includes first shock absorber 20 afunctioning as a first chamber that defines first gas chamber 21 a, andsecond shock absorber 20 b functioning as a second chamber that definessecond gas chamber 21 b. First shock absorber 20 a and second shockabsorber 20 b are mutually different shock absorbers. First gas chamber21 a defined by first shock absorber 20 a and second gas chamber 21 bdefined by second shock absorber 20 b are mutually independent from oneanother, and are not in fluid communication with one another. Morespecifically, partition 27 is disposed between and separates first gaschamber 21 a and second gas chamber 21 b. Partition 27 is made of thesame sheet material used for balloon 20.

In gas chamber 21 made of the sheet material, first gas chamber 21 acontains a first gas that is less dense than air, and second gas chamber21 b contains a second gas that is more dense than the first gas. Inthis embodiment, for example, the first gas is helium and the second gasis air.

As illustrated in FIG. 5, balloon 20 has rotational symmetry about anaxis of symmetry extending in the up-and-down direction (line extendingvertically out from the drawing in FIG. 5). This axis of symmetry iscentral axis P of balloon 20. Balloon 20 illustrated in FIG. 5 has arotational symmetry of 90 degrees. In other words, balloon 20 has thesame shape after each 90 degree rotation about central axis P.

As illustrated in FIG. 6, balloon 20 has a flattened shape. Morespecifically, the height axis of balloon 20 is flattened. Moreover, whenviewed from a lateral side, balloon 20 has a streamline shape. Balloon20 gradually decreases in height from its central region toward itsperipheral edge. More specifically, in a cross section of balloon 20taken along central axis P illustrated in FIG. 6, balloon 20 has anelliptical shape whose major axis extends horizontally and minor axisextends vertically. Stated differently, balloon 20 has a cross sectionalshape that is approximately symmetrical about its horizontal axis. Notethat the cross sectional shape of balloon 20 need not be a preciseellipse; it may be a shape that would be recognized as an ellipse at aglance.

Balloon 20 includes as many ventilation holes 22 as it does rotor units30 (four in this embodiment). As illustrated in FIG. 6, each ventilationhole 22 is a passageway having an approximately circular cross section,and passes through balloon 20 in the up-and-down direction. Central axisQ of each ventilation hole 22 is approximately parallel to central axisP of balloon 20. Each ventilation hole 22 extends across first shockabsorber 20 a and second shock absorber 20 b.

As illustrated in FIG. 6, central axis Q of each ventilation hole 22 islocated between (i) a center point between central axis P of balloon 20and the peripheral edge of balloon 20 and (ii) the peripheral edge ofballoon 20. More specifically, the distance S between central axis P ofballoon 20 and central axis Q of ventilation hole 22 is longer than halfof the distance R between central axis P of balloon 20 and theperipheral edge of balloon 20 (S>R/2). Thus, rotor units 30 are locatedcloser to the peripheral edge of balloon 20 than central axis P ofballoon 20. Arranging rotor units 30 in this manner makes it possible tosecure enough space between rotor units 30 and stably fly aircraft 10.

The cross sectional area of each ventilation hole 22 is smallest in thecentral region, in the up-and-down direction, of ventilation hole 22(i.e., the area of a cross section taken perpendicular to central axis Qis smallest in the central region of ventilation hole 22). Eachventilation hole 22 has a shape that gradually expands in crosssectional area from the central region in the up-and-down directiontoward the top end portion and from the vertical central region towardthe bottom end portion. Stated differently, each ventilation hole 22 hasthe shape of a pillar with a pinched midsection. As described above,balloon 20 gradually decreases in height from its central region towardits peripheral edge. As such, with respect to each ventilation hole 22,the height h measured closer to the peripheral edge of balloon 20 isless than the height H measured closer to the central region of balloon20.

As illustrated in FIG. 5, four ventilation holes 22 are arranged at 90degree intervals around central axis P of balloon 20. Central axes Q ofventilation holes 22 are equidistant from central axis P of balloon 20.Stated differently, central axis Q of each ventilation hole 22 isapproximately orthogonal to one pitch circle PC centered on central axisP of balloon 20.

As illustrated in FIG. 5, in a top view, the peripheral edge of balloon20 includes reference curve sections 23 and small curvature radiussections 24. There are the same number of reference curve sections 23 asthere are ventilation holes 22 and the same number of small curvatureradius sections 24 as there are ventilation holes 22 (four in thisembodiment). Reference curve sections 23 and small curvature radiussections 24 are alternately arranged around the peripheral edge ofballoon 20 in a top view. Each small curvature radius section 24 isarranged outward of a different one of ventilation holes 22 (here,“outward” means on a side opposite central axis P of balloon 20). Eachreference curve section 23 is disposed between two adjacent smallcurvature radius sections 24.

Reference curve sections 23 and small curvature radius sections 24 areboth curved lines. The midpoint of the length (in the circumferentialdirection) of each small curvature radius section 24 is located on lineL that intersects central axis Q of the closest ventilation hole 22 aswell as central axis P of balloon 20 at right angles.

The radius of curvature of each small curvature radius section 24 isshorter than the radius of curvature of each reference curve section 23.However, the radius of curvature of each reference curve section 23 neednot be constant throughout the length of reference curve section 23. Theradius of curvature of each small curvature radius section 24 also neednot be constant throughout the length of small curvature radius section24. When the radius of curvature of reference curve sections 23 andsmall curvature radius sections 24 is not constant, the maximum radiusof curvature of each small curvature radius section 24 may be less thanthe minimum radius of curvature of each reference curve section 23.

As illustrated in FIG. 6, balloon 20 includes a tubular coupler 25.Coupler 25 is made of a transparent sheet material shaped into acylinder (or round tube) whose top and bottom end portions have aslightly increased diameter. Coupler 25 is disposed such that itscentral axis is approximately coaxial with central axis P of balloon 20.Inside balloon 20, the top end of coupler 25 is connected to the upperportion of balloon 20 and the bottom end of coupler 25 is connected tothe lower portion of balloon 20.

The top end of the tubular coupler 25 is sealed, whereas the bottom endis open. The space inside coupler 25 is therefore in fluid communicationwith the space outside balloon 20. Air is present in the space insidecoupler 25, and the pressure inside the space is essentially the same asthe atmospheric pressure.

As described above, balloon 20 has rotational symmetry about centralaxis P extending in the up-and-down direction. The first gas, such ashelium, that fills first gas chamber 21 a of balloon 20 is evenlydistributed throughout the entire first gas chamber 21 a. Similarly, thesecond gas, such as air, that fills second gas chamber 21 b of balloon20 is evenly distributed throughout the entire second gas chamber 21 b.Accordingly, the working point of the buoyant force (center of buoyancy)imparted by the first gas in balloon 20 is located approximately oncentral axis P of balloon 20.

As illustrated in FIG. 2, FIG. 4, and FIG. 5, aircraft 10 furtherincludes release unit 26 that is disposed on the upper portion of firstshock absorber 20 a of balloon 20 and releases the first gas containedin first gas chamber 21 a at a predetermined timing (for example, uponreceipt of an instruction from controller 41 to release the first gas).Release unit 26 includes a valve that selectively places first gaschamber 21 a in fluid communication with the outside space. The valveis, for example, an electromagnetic valve. In other words, release unit26 releases the first gas contained in first gas chamber 21 a to theoutside space by opening the valve at a predetermined timing.

Balloon 20 includes a plurality of ducts 28 that communicatively connectthe plurality of ventilation holes 22. More specifically, the pluralityof ducts 28 communicatively connect the space inside coupler 25, whichis located in the center of balloon 20 in a top view, with each of theplurality of ventilation holes 22. A part of fixing component 50 isdisposed inside each of the plurality of ducts 28. In other words, theplurality of ducts 28 define spaces for accommodating part of fixingcomponent 50.

Balloon 20 includes recess 29 of a size capable of housing one or moreon-board devices including camera 44. The opening of recess 29 islocated on the bottom end of coupler 25.

Moreover, protective nets 62 and 63 are provided at the top and bottomportions of ventilation holes 22 of balloon 20 to inhibit contact withrotor units 30 disposed inside ventilation holes 22 in the event that anobject contacts the upper or lower portion of ventilation holes 22.

In this embodiment, the inner volumetric capacity of balloon 20 (i.e.,the volumetric capacity of gas chamber 21) is determined such that thebuoyant force of the gas filling balloon 20 is slightly more than thegross weight of aircraft 10. Thus, aircraft 10 slowly ascends even ifthe plurality of rotor units 30 stop mid-air.

(Rotor Units)

Next, rotor units 30 will be described.

As illustrated in FIG. 2 and FIG. 3, each rotor unit 30 includespropeller 32 and motor 33.

Motors 33 are attached to arms 52 of fixing component 50 (to bedescribed later). Propellers 32 are attached to the output shafts ofmotors 33. Note that each rotor unit 30 may include two propellers 32that coaxially rotate in opposite directions. In other words, each rotorunit 30 may include contra-rotating propellers.

One rotor unit 30 is disposed in each ventilation hole 22. Rotor units30 are oriented such that the axes of rotation of propellers 32 areapproximately vertical. The axes of rotation of propellers 32 areapproximately coaxial with central axes Q of ventilation holes 22. Rotorunits 30 are disposed in the central regions of ventilation holes 22 inthe up-and-down direction. In other words, as illustrated in FIG. 3,rotor units 30 are disposed so as to overlap central plane M in theup-and-down direction of balloon 20. This central plane M is located inthe central region of balloon 20 in the up-and-down direction, and isorthogonal to central axis P of balloon 20. The outer diameter of eachrotor unit 30 is roughly equal to the inner diameter of the centralregion of ventilation hole 22 in the up-and-down direction.

Each rotor unit 30 is disposed such that the entire height fits withinventilation hole 22. In other words, each rotor unit 30 is laterallycovered by balloon 20, across the height of rotor unit 30 in theup-and-down direction. In particular, each rotor unit 30 is laterallycovered by second shock absorber 20 b of balloon 20, across the heightof rotor unit 30 in the up-and-down direction. Note that the“up-and-down direction” refers to the up and down directions whenaircraft 10 is horizontally level and not tilted. In other words, theup-and-down direction is approximately parallel to the axis of rotationof each rotor unit 30.

Each ventilation hole 22 preferably has a height such that distancesfrom the center in the up-and-down direct of rotor unit 30 to the topand to the bottom are each greater than or equal to the radius of rotorunit 30. With this, when rotor unit 30 receives an impact or breaks, forexample, even if the axis of rotation of propeller 32 of rotor unit 30were to rotate 90 degrees relative to aircraft 10, rotor unit 30 can beinhibited from projecting out of ventilation hole 22. Accordingly,balloon 20 can laterally cover rotor unit 30 to a degree such that rotorunit 30 is not likely to contact an object.

(On-Board Devices, Light Emitter)

As described above, aircraft 10 is provided with, as on-board devices,controller 41, battery 42, projector 43, and camera 44. Aircraft 10 isfurther provided with light emitter 46.

As illustrated in FIG. 3, aircraft 10 includes disc 40. Disc 40 is adisc-shaped component whose diameter is substantially equal to thebottom end of coupler 25. Disc 40 is disposed so as to cover the bottomend surface of coupler 25. Disc 40 may be made of a resin material suchas polypropylene (PP), polycarbonate (PC), polybutylene terephthalate(PBT), or ABS resin, and may be made of a metal material such asaluminum, copper, or stainless steel.

Camera 44, which is used for capturing images, is attached to the bottomsurface of disc 40 via gimbal 45. Camera 44 is for capturing aerialvideo, and is angled diagonally downward. As illustrated in FIG. 3 andFIG. 4, camera 44 protrudes beyond balloon 20 in a downward directionalong a predetermined axis. Gimbal 45 is for holding camera 44 at asteady angle, even if the orientation of aircraft 10 changes.

Controller 41, battery 42, and projector 43 are disposed on top of disc40. Controller 41 is a device that controls operation of plurality ofrotor units 30. In this embodiment, controller 41 includes receiver 41 athat receives an instruction signal transmitted from a radio controldevice functioning as a control terminal operated by an operator.Controller 41 controls rotor units 30, camera 44, projector 43, and LEDsbased on the instruction signal received by receiver 41 a. Controller 41also transmits video captured by camera 44.

Note that controller 41 having the functions described above isimplemented as a computer including, for example, a central processingunit (CPU), random access memory (RAM), read only memory (ROM),communications interface, and an I/O port.

Battery 42 supplies power to rotor units 30, controller 41, projector43, and light emitter 46. Projector 43 projects video onto the innersurface of balloon 20, which is made of a semi-transparent material.

Light emitter 46 is an LED light strip including an elongated flexibleprinted substrate and multiple light-emitting elements (such as LEDs)aligned in the lengthwise direction of the elongated flexible printedsubstrate

Note that aircraft 10 may include only one device among projector 43,camera 44, and light emitter 46, and, alternatively, may include all ofthe devices. Aircraft 10 may also include other types of devices such asa speaker and/or a display panel. In other words, aircraft 10 need onlyinclude devices for achieving basic flight, such as rotor units 30;aircraft 10 may include devices that do not essentially contribute toflight, such as projector 43 and camera 44, on an as-needed basisaccording to the needs of the user.

(Fixing Component)

Fixing component 50 fixes the plurality of rotor units 30 inpredetermined positions in a plan view and fixes the plurality of rotorunits 30 such that the axes of rotation of the plurality of rotor units30 are substantially parallel to the up-and-down direction. Morespecifically, fixing component 50 includes main body 51, four arms 52,and two holding components 54.

Main body 51 is a cylindrical component having a bottom in the upperportion. Main body 51 is disposed inside the space on the inner side ofcoupler 25. Stated differently, main body 51 defines a space therein.

The four arms 52 are tubular components that are fixed to the sidesurface of main body 51, and extend in four different directions fromthe side surface of main body 51. Here, four different directions aredirections toward each of the plurality of ventilation holes 22 from thespace on the inner side of coupler 25. The four arms 52 are disposedinside ducts 28.

The four arms 52 include distal end sections 52 a that fix the fourrotor units 30 such that the axes of rotation of the four rotor units 30are substantially parallel to the up-and-down direction. Morespecifically, the lower portion of motors 33 of rotor units 30 are fixedto distal end sections 52 a.

The two holding components 54 are fixed to the lower portion of mainbody 51, and extend downward from main body 51. The bottom ends of thetwo holding components 54 hold disc 40 that supports on-board devices.

Note that main body 51 includes, where the four arms 52 are fixedthereto, through-holes for fluid communication with the inner space ofmain body 51. With these, the inner space of main body 51 is in fluidcommunication with spaces inside the four arms 52. The spaces inside thefour arms 52 house electrical wiring (not illustrated) for supplyingpower from battery 42 to the plurality of rotor units 30. That is, thefour arms 52 also function as conduit for housing electrical wiring.

Note that fixing component 50 may be supported by balloon 20 as a resultof the plurality of arms 52 being held in the plurality of ducts 28under pressure from second gas chamber 21B, and, alternatively, mainbody 51 may be fixed in a predetermined position on coupler 25. In otherwords, fixing component 50 may be fixed by any means so long as it isfixed in a predetermined position relative to balloon 20.

Disc 40 supports housing 55 that houses a weight in addition to theon-board devices. Stated differently, aircraft 10 includes housing 55.Housing 55 is a box-shaped component that defines a space that can housea metal (e.g., lead, copper, alloy) weight. Note that the weight is notlimited to a metal weight; the weight may be a non-metal weight (such assand). The weight is capable of adjusting the gross weight of aircraft10 in predetermined units of weight (for example, 1 to 10 grams).

Since balloon 20 is made of a stretchable material, it is difficult toset the amount of gas to be filled in gas chamber 21 (stateddifferently, to set the volumetric area of gas chamber 21). Accordingly,it is difficult to estimate the magnitude of the buoyant force impartedby the gas without error before the gas is filled in gas chamber 21 ofballoon 20.

Accordingly, by providing housing 55, after gas is filled into gaschamber 21 of balloon 20, the gross weight of aircraft 10 can beadjusted by adding or removing weights to or from housing 55. With this,as described in Embodiment 1, it is easy to adjust the gross weight ofaircraft 10 such that the magnitude of the buoyant force imparted by thegas filling balloon 20 is slightly greater than the gross weight ofaircraft 10. Note that the magnitude of the buoyant force imparted bythe gas is set so as to always be greater than the gross weight ofaircraft 10 when no weights are housed in housing 55, even when thereare slight differences in volumetric area between gas chambers 21 ofballoons 20.

Voltage regulators 53 are provided to the four arms 52. Voltageregulators 53 are amplifiers that adjust the voltage of the power thatdrives the respective motors 33 included in rotor units 30 disposed onarms 52. Voltage regulators 53 are disposed in ventilation holes 22.

(Flying Orientation of Aircraft)

As described above, in aircraft 10, on-board devices such as controller41 and battery 42 are disposed in the lower end portion of the spaceinside coupler 25. In other words, the relatively heavy on-board devicesare clustered in the lower portion of aircraft 10. Accordingly, theoverall center of gravity of aircraft 10 is lower than the working pointof the buoyant force imparted by the gas filling balloon 20. With this,even when rotor units 30 are stopped, aircraft 10 can maintain anorientation in which camera 44 is oriented downward, without rotatinghorizontally or flipping top over bottom, for example.

Moreover, relatively heavy on-board devices are disposed below rotorunits 30. As a result, the overall center of gravity of aircraft 10 islower than the working point of the buoyant force imparted by rotorunits 30 operating. With this, even when rotor units 30 are operating,aircraft 10 can maintain an orientation in which camera 44 is orienteddownward.

Aircraft 10 includes a plurality of rotor units 30. When moving aircraft10 in a substantially horizontal direction, increasing the rotationalspeed of a rotor unit 30 located further in the opposite direction oftravel to a speed greater than the rotational speed of a rotor unit 30located further in the direction of travel allows aircraft 10 toincrease propulsion in a horizontal direction.

Note that the “rotational speed of a rotor unit 30” means the rotationalspeed of propeller 32 included in the rotor unit 30 (revolutions ofpropeller 32 per unit time).

(Aircraft Operation Control Example)

With aircraft 10 according to this embodiment, gas release control isperformed at a predetermined timing. That is to say, release unit 26 iscontrolled so as to release the first gas contained in first gas chamber21 a at a predetermined timing.

Next, this gas release control according to aircraft 10 will bedescribed with reference to FIG. 7 through FIG. 9.

FIG. 7 is a block diagram illustrating a configuration of aircraft 10according to Embodiment 1. Note that illustration of some elements, suchas battery 42 and camera 44, are omitted in FIG. 7. FIG. 8A is a flowchart of one example of the gas release control in aircraft 10 accordingto Embodiment 1. FIG. 8B is a flow chart of another example of the gasrelease control in aircraft 10 according to Embodiment 1. FIG. 9illustrates aircraft 10 according to Embodiment 1 when gas releasecontrol is performed. Note that FIG. 9 is the same cross section asillustrated in FIG. 4.

As illustrated in FIG. 7, aircraft 10 includes a plurality (in thisembodiment, four) rotor units 30, controller 41, release unit 26, anddetector 80. The plurality of rotor units 30 generate thrust for flyingaircraft 10.

Controller 41 controls the rotation of propellers 32 of the plurality ofrotor units 30. Controller 41 includes receiver 41 a that receives aninstruction signal transmitted from a radio control device. Controller41 controls the rotation of propellers 32 of the plurality of rotorunits 30 in accordance with a flight instruction signal transmitted fromthe radio control device. Receiver 41 a may also receive signals otherthan the above-described instruction signal.

Detector 80 detects an abnormal state of aircraft 10, and transmits anabnormal state signal indicating the result of the detection tocontroller 41.

More specifically, detector 80 may monitor the state of battery 42, and,for example, may detect that battery 42 has no charge or is low oncharge as an abnormal state of aircraft 10. Note that battery 42 beinglow on charge is a state in which the charge capacity is 10% or lesswhere a charge capacity of 100% represents a state in which battery 42is fully charged.

Detector 80 may detect, as an abnormal state of aircraft 10, thataircraft 10 is not descending even though receiver 41 a has received aninstruction signal instructing aircraft 10 to descend. Morespecifically, detector 80 may monitor the operational state of rotorunits 30, and detector 80 may detect, as an abnormal state of aircraft10, that rotor units 30 are not being rotated so as to generate thrustthat causes aircraft 10 to descend, even though receiver 41 a hasreceived an instruction signal instructing aircraft 10 to descend.Detector 80 may detect the elevation of aircraft 10, and detect, as anabnormal state of aircraft 10, that the elevation of aircraft 10 is notdecreasing even though receiver 41 a has received an instruction signalinstructing aircraft 10 to descend.

Controller 41 transmits a release command to release unit 26 inaccordance with a release instruction signal transmitted from the radiocontrol device.

Although not illustrated in FIG. 7, note that aircraft 10 includesballoon 20 that functions as a shock absorber, as described above.

In aircraft 10 having the configuration described above, the gas releasecontrol may be implemented via, for example, the information processingand operations illustrated in FIG. 8A. In other words, detector 80detects an abnormal state of aircraft 10 (S11). Controller 41 releasesthe first gas contained in first gas chamber 21 a to the outside spaceby switching release unit 26 to an open state (S12). In other words, inthe gas release control illustrated in FIG. 8A, release unit 26 releasesthe first gas contained in first gas chamber 21 a, when, as thepredetermined timing, detector 80 detects an abnormal state.

In aircraft 10 having the configuration described above, the gas releasecontrol may be implemented via, for example, the information processingand operations illustrated in FIG. 8B. In other words, receiver 41 areceives a release instruction signal transmitted from the radio controldevice (S11 a). Controller 41 releases the first gas contained in firstgas chamber 21 a to the outside space by switching release unit 26 to anopen state (S12). Stated differently, in the gas release controlillustrated in FIG. 8B, release unit 26 releases the first gas containedin first gas chamber 21 a, when, as the predetermined timing, receiver41 a receives a release instruction signal indicating release of thefirst gas contained in first gas chamber 21 a.

By performing one of the gas release controls described with referenceto FIG. 8A and FIG. 8B, the valve in release unit 26 places first gaschamber 21 a in fluid communication with the outside space, asillustrated in FIG. 9. This releases the first gas contained in thefirst gas chamber 21 a to the space outside first gas chamber 21 a.Since the released first gas is less dense than air, the specificgravity of aircraft 10 gradually becomes heavier as the first gas isreleased, and the magnitude of the buoyant force imparted by the gasthat filled first gas chamber 21 a decreases to less than the grossweight of aircraft 10. Aircraft 10 then begins to descend.

(Advantageous Effects, Etc., of Embodiment 1)

Aircraft 10 according to this embodiment includes: a plurality of rotorunits 30, each of which includes propeller 32 and motor 33 that drivespropeller 32; balloon 20 including first shock absorber 20 a thatdefines first gas chamber 21 a containing a first gas less dense thanair and second shock absorber 20 b that is different than first shockabsorber 20 a; and release unit 26 that is disposed in first shockabsorber 20 a and releases the first gas contained in first gas chamber21 a, at a predetermined timing.

With this configuration, since the first gas that is less dense than aircan be released via release unit 26 at a predetermined timing, forexample, when aircraft 10 becomes uncontrollable mid-flight, aircraft 10can be made to swiftly descend. Moreover, even if the first gas isreleased, since the state of second shock absorber 20 b can bemaintained, when aircraft 10 descends, the plurality of rotor units 30and on-board devices in aircraft 10 such as camera 44 can be inhibitedfrom directly contacting an object on the ground or a floating objectbefore landing. Accordingly, even in cases in which aircraft 10 isbrought down to the land by releasing the first gas, the plurality ofrotor units 30, the on-board devices of aircraft 10, and/or the objectcan be prevented from being damaged.

Moreover, in this embodiment, second shock absorber 20 b is disposed atleast in the lower portion of aircraft 10. Accordingly, it is possibleto maintain the state of second shock absorber 20 b disposed on thelower portion of aircraft 10, even when aircraft 10 is caused to descendby releasing the first gas. As such, even while aircraft 10 isdescending, the plurality of rotor units and other on-board devices ofthe aircraft can be effectively inhibited from directly contacting anobject.

Moreover, in this embodiment, second shock absorber 20 b laterallycovers the plurality of rotor units 30, across a height of the pluralityof rotor units 30 in the up-and-down direction. Accordingly, it ispossible to maintain the state of second shock absorber 20 b thatlaterally covers the plurality of rotor units 30, across a height of theplurality of rotor units 30 in the up-and-down direction, even whenaircraft 10 is caused to descend by releasing the first gas. As such,even while aircraft 10 is descending, the plurality of rotor units 30can be effectively inhibited from directly contacting an object.

Moreover, in this embodiment, second shock absorber 20 b defines secondgas chamber 21 b containing a second gas that is more dense than thefirst gas. This makes it possible to implement second shock absorber 20b with a simple configuration.

Moreover, in this embodiment, first shock absorber 20 a is disposed inthe upper portion of aircraft 10. This makes it possible to efficientlyrelease the first gas, which is less dense than air, contained in firstgas chamber 21 a defined by first shock absorber 20 a. It also makes itpossible to position the center of gravity of aircraft 10 in the lowerportion of aircraft 10 and thus inhibit aircraft 10 from flipping topover bottom.

Moreover, in this embodiment, release unit 26 includes a valve thatselectively places the first gas chamber in fluid communication with theoutside space. In other words, release unit 26 releases the first gascontained in the first gas chamber to the outside space by opening thevalve at a predetermined timing. This makes it possible to implement asimple configuration for releasing the first gas via release unit 26 ata predetermined timing.

Moreover, in this embodiment, release unit 26 is configured as anelectromagnetic valve capable of freely switching between open andclosed states. Accordingly, even after the gas release control has beenperformed and the first gas has been released, aircraft 10 can be reusedif first shock absorber 20 a of aircraft 10 is reinflated with the firstgas.

Moreover, in this embodiment, aircraft 10 further includes receiver 41 athat receives a signal. Furthermore, the predetermined timing is whenreceiver 41 a receives a release instruction signal indicating releaseof the first gas contained in the first gas chamber 21 a. Release unit26 releases the first gas contained in the first gas chamber whenreceiver 41 a receives the release instruction signal. This makes itpossible to release the first gas via release unit 26 by, for example,an operator using a control terminal to transmit a release instructionsignal. With this, the operator can cause aircraft 10 to swiftly descendby releasing the first gas via release unit 26 at a predeterminedtiming.

Moreover, in this embodiment, aircraft 10 further includes detector 80that detects an abnormal state of the aircraft. Furthermore, thepredetermined timing is when the abnormal state is detected by detector80. Release unit 26 releases the first gas contained in first gaschamber 21 a when detector 80 detects an abnormal state. This makes itpossible to release the first gas via release unit 26 when aircraft 10is in an abnormal state. This in turn makes it possible for aircraft 10to automatically descend in the case of an abnormal state.

Moreover, in this embodiment, aircraft 10 further includes receiver 41 athat receives an instruction signal transmitted from a control terminaloperated by an operator. Detector 80 detects, as the abnormal state,that aircraft 10 is not descending even though receiver 41 a hasreceived an instruction signal instructing aircraft 10 to descend. Thismakes it possible to release the first gas via release unit 26 whenaircraft 10 is in an abnormal state, namely, when aircraft 10 cannotdescend. This in turn makes it possible for aircraft 10 to automaticallydescend in the case of an abnormal state in which aircraft 10 cannotdescend even when instructed to do so by the operator.

Moreover, in this embodiment, balloon 20 has a flattened shape in theup-and-down direction.

This makes it less likely that aircraft 10 will tilt relative to theaxis of symmetry (central axis P) of balloon 20 mid-flight, resulting ina more stable flight of aircraft 10.

Moreover, in this embodiment, rotor units 30 and ventilation holes 22 inwhich rotor units 30 are disposed are located closer to the peripheraledge of balloon 20 than central axis P of balloon 20.

Accordingly, in aircraft 10, sufficient space between the plurality ofrotor units 30 can be secured. Thus, according to this embodiment, sincesufficient space between the plurality of rotor units 30 can be secured,flight of aircraft 10 can be stabilized.

Moreover, in this embodiment, balloon 20 gradually decreases in heightfrom its central region toward its peripheral edge.

With this, when viewed from a lateral side, balloon 20 has a streamlineshape. Thus, according to this embodiment, it is possible to reduce theresistance of aircraft 10 to air mid-flight. Furthermore, whenventilation holes 22 are arranged at intervals of a predetermined anglearound the central axis of balloon 20 extending in the up-and-downdirection, ventilation holes 22 are located at relatively slim portionsof balloon 20, making it possible to keep the lengths of ventilationholes 22 relatively short. The shorter the lengths of ventilation holes22, the less the loss in air pressure is as air passes throughventilation holes 22. Thus, in this case, it is possible to secure asufficient amount of air flow through ventilation holes 22, which makesit possible to secure sufficient propulsion by rotor units 30.

Moreover, in this embodiment, coupler 25 is provided in the centralregion of balloon 20 with one end connected to the upper portion ofballoon 20 and the other end connected to the lower portion of balloon20.

In other words, in the central region of balloon 20, the upper portionand lower portion of balloon 20 are connected via coupler 25.Accordingly, balloon 20 can easily assume a desired shape, such as aflattened shape. When the shape of balloon 20 is stable, ventilationholes 22 formed in balloon 20 are also stable, making it possible toachieve actual ventilation holes 22 similar to their design shape. Thus,it is possible to secure a sufficient amount of air flow throughventilation holes 22, which makes it possible to secure sufficientpropulsion by rotor units 30. Moreover, stabilizing the shape ofventilation holes 22 formed in balloon 20 makes it easier toapproximately match the shapes of all ventilation holes 22. This furtherequalizes the amount of air flowing through ventilation holes 22, whichstabilizes the flight of aircraft 10.

Moreover, in this embodiment, coupler 25 has a tubular shape.

As such, the central regions of the upper and lower portions of balloon20 (i.e., the regions surrounding central axis P of balloon 20) areconnected to one another via tubular coupler 25, across the entireperimeter of the central regions. Thus, according to this embodiment, itis further easier for balloon 20 to maintain a desirable shape.

Moreover, in this embodiment, the space inside coupler 25 is in fluidcommunication with the space outside balloon 20.

As such, air fills the space inside coupler 25 rather than gas forexerting buoyant force, such as helium.

Moreover, in this embodiment, each ventilation hole 22 has a shape thatgradually expands in cross sectional area from the central region in theup-and-down direction toward the top end portion and from the centralregion in the up-and-down direction toward the bottom end portion.

Giving ventilation holes 22 such a shape reduces a loss in air pressureas air flows into ventilation holes 22 and a loss in air pressure as airflows out of ventilation holes 22. As such, even when rotor units 30generate little thrust, it is possible to secure a sufficient amount ofair flow through ventilation holes 22, which makes it possible to securesufficient propulsion by rotor units 30. Thus, since the same thrust isachieved, it is possible to reduce the amount of energy used by rotorunit 30.

Moreover, in this embodiment, balloon 20 gradually decreases in heightfrom its central region toward its peripheral edge, and with respect toeach ventilation hole 22, the height h measured near the peripheral edgeof balloon 20 is less than the height H measured near the central regionof balloon 20.

With this, in each ventilation hole 22 in balloon 20, air flows intoventilation hole 22 from a direction originating from the peripheraledge of balloon 20 and exits ventilation hole 22 in a direction headingtoward the peripheral edge of balloon 20. As a result, air flowing intoone ventilation hole 22 can be inhibited from interfering with airflowing into another ventilation hole 22, and air flowing out of oneventilation hole 22 can be inhibited from interfering with air flowingout of another ventilation hole 22. Thus, according to this embodiment,disruption of airflow due to interference of air flowing into and out ofventilation holes 22 can be inhibited, which stabilizes flight ofaircraft 10.

Moreover, in this embodiment, rotor units 30 are disposed in the centralregions in the up-and-down direction of ventilation holes 22. In otherwords, rotor units 30 are disposed so as to overlap a central plane inthe up-and-down direction of balloon 20.

As such, air flowing from the top of ventilation hole 22 toward rotorunit 30 and air flowing from rotor unit 30 toward the bottom ofventilation hole 22 can be stabilized, which stabilizes flight ofaircraft 10.

Moreover, in this embodiment, ventilation holes 22 are arranged atintervals of a predetermined angle around central axis P of balloon 20extending in the up-and-down direction.

Since the plurality of rotor units 30 are therefore disposed atintervals of a predetermined angle around central axis P of balloon 20and blow air downward, flight of aircraft 10 can be stabilized.

Moreover, in this embodiment, balloon 20 has rotational symmetry about aline extending in the up-and-down direction.

As such, the working point of the buoyant force imparted by the gasfilling balloon 20 can be located on the axis of symmetry (i.e., centralaxis P) of balloon 20. As such, aircraft 10 can be inhibited fromtilting mid-flight (i.e., tilt relative to the up-and-down (vertical)direction of central axis P of balloon 20), which stabilizes flight ofaircraft 10.

Moreover, in this embodiment, in a top view, the peripheral edge ofballoon 20 includes reference curve sections 23 and small curvatureradius sections 24 having a smaller radius of curvature than referencecurve sections 23. Reference curve sections 23 and small curvatureradius sections 24 are alternately arranged around the peripheral edge.There are the same number of reference curve sections 23 as there areventilation holes 22 and the same number of small curvature radiussections 24 as there are ventilation holes 22. Each small curvatureradius section 24 is disposed adjacent to a different one of ventilationholes 22, in a more peripheral position than the ventilation hole 22 itis disposed adjacent to.

Here, tension working in sections of the peripheral edge of balloon 20in a top view near ventilation holes 22 is lower than tension working insections of the peripheral edge of balloon 20 in a top view further awayfrom ventilation holes 22. This is because tension is working onportions of balloon 20 that form the walls of ventilation holes 22. Whentension working on balloon 20 is regionally low, wrinkles easily formwhere working tension is low.

In light of this, in this embodiment, the radius of curvature ofsections of the peripheral edge of balloon 20 in a top view nearventilation holes 22 is less than the radius of curvature of sections ofthe peripheral edge of balloon 20 in a top view further from ventilationholes 22. As such, the difference between tension working in sections ofthe peripheral edge of balloon 20 in a top view near ventilation holes22 and tension working in sections of the peripheral edge of balloon 20in a top view further away from ventilation holes 22 can be reduced.Thus, according to this embodiment, wrinkles can be kept from forming inballoon 20, and the aesthetics of balloon 20 can be maintained.

Moreover, in this embodiment, on-board devices are housed in the spaceinside coupler 25. The housed on-board devices include at leastcontroller 41 that controls rotor units 30 and battery 42 that suppliespower to rotor units 30.

The space inside coupler 25 is in fluid communication with the spaceoutside balloon 20. As such, maintenance such as changing battery 42disposed in the space inside coupler 25 can be done without releasingthe gas for providing buoyancy, such as helium, from balloon 20.

Moreover, in this embodiment, on-board devices are disposed at thebottom end portion of the space inside coupler 25.

As such, the center of gravity of aircraft 10 can be lowered, therebystabilizing flight of aircraft 10.

Moreover, in this embodiment, coupler 25 is transparent, and lightemitter 46 is housed in the space inside coupler 25.

In this embodiment, light emitted by light emitter 46 passes through thetransparent coupler 25. As such, if the outer layer of balloon 20 ismade of a semi-transparent material, for example, light emitted by lightemitter 46 will strike the inner surface of balloon 20, whereby thecolor of the entire balloon 20 can be changed to the color of lightemitted by light emitter 46. Thus, according to this embodiment, thecolor of balloon 20 can be changed mid-flight to easily achieve adramatic effect, for example.

Variations of Embodiment 1

Variation 1

In aircraft 10 according to Embodiment 1, release unit 26 is implementedas a valve, but release unit 26 is not limited to this example. Forexample, as illustrated in FIG. 10, aircraft 10A includes balloon 20Ahaving, instead of release unit 26, hole opener 26Aa that opens a holein a predetermined region of first shock absorber 20Aa. FIG. 10illustrates aircraft 10A according to Variation 1 of Embodiment 1 whengas release control is performed. In FIG. 10, (a) illustrates the wholeaircraft 10A after gas release control has been performed, and (b)illustrates enlarged views of release unit 26A of aircraft 10 before andafter gas release control is performed. Note that FIG. 10 is the samecross section as illustrated in FIG. 4.

As illustrated in (b-1) in FIG. 10, in a state before gas releasecontrol has been performed, release unit 26A is disposed on the upperportion of first shock absorber 20Aa in aircraft 10A. Release unit 26Aincludes, for example, hole opener 26Aa including gunpowder capable ofcreating a small explosion. Hole opener 26Aa creates a small explosionupon receiving a release command from controller 41 at a predeterminedtiming ((b-2) in FIG. 10) that opens hole 26Ac in first shock absorber20Aa, which places first gas chamber 21Aa in fluid communication withthe outside space ((b-3) in FIG. 10). This releases the first gascontained in the first gas chamber 21Aa to the space outside first gaschamber 21Aa. Since the released first gas is less dense than air, thespecific gravity of aircraft 10A gradually becomes heavier as the firstgas is released, and the magnitude of the buoyant force imparted by thegas that filled first gas chamber 21Aa decreases to less than the grossweight of aircraft 10A. Aircraft 10A then begins to descend.

In this way, with aircraft 10A according to Variation 1 of Embodiment 1,release unit 26A is configured to open hole 26Ac in first shock absorber20Aa, which places first gas chamber 21Aa in fluid communication withthe outside space. Release unit 26A releases the first gas contained infirst gas chamber 21Aa to the outside space at a predetermined timing byopening hole 26Ac. This makes it possible to implement a simpleconfiguration for releasing the first gas via release unit 26A at apredetermined timing.

Note that, as illustrated in (b-1) in FIG. 10, region 26Ab in which hole26Ac is opened in first shock absorber 20Aa is preferably more fragilethan other regions of first shock absorber 20Aa. More specifically,region 26Ab in which hole 26Ac is opened may be made to be fragile bybeing thinner than other regions of first shock absorber 20Aa or bybeing made of a more fragile material than the vinyl chloride materialused to make first shock absorber 20Aa (e.g., latex). This makes it easyto open hole 26Ac in the region of first shock absorber 20Aa where hole26Ac is to be formed.

Moreover, the hole opener is not limited to opening the hole via a smallexplosion. The hole opener may open a hole in region 26Ab in which hole26Ac is to be formed using a needle or sharp blade. In other words, thehole opener is not limited to the above example, and may have anyconfiguration that can open a hole in first shock absorber 20Aa.

Variation 2

Moreover, aircraft 10B may be implemented by adding, to aircraft 10according to Embodiment 1, compression components 71 for speeding up thereleasing of the first gas when the gas release control is performed.FIG. 11 illustrates aircraft 10B according to Variation 2 of Embodiment1 when gas release control is performed. Note that (a) in FIG. 11illustrates aircraft 10B before the gas release control is performed,and corresponds to the cross section as illustrated in FIG. 4. Note that(b) in FIG. 11 illustrates the overall state of aircraft 10B after thegas release control has been performed.

As illustrated in FIG. 11, inside first shock absorber 20 a of aircraft10B, compression components 71 are implemented as compression springs,which are disposed in a state in which they are expanded beyond theirresting state. The respective ends of each compression component 71 areconnected to the upper portion and lower portion of first shock absorber20 a. Stated differently, compression components 71 are connected to theupper portion and lower portion of first shock absorber 20 a in a statein which a compressive force is exerted that pulls the upper portion andlower portion of first shock absorber 20 a toward one another. In thisway, even though compression components 71 exert a compressive forcethat pulls the upper portion and the lower portion of first shockabsorber 20 a toward one another, since first gas chamber 21 a of firstshock absorber 20 a is filled with the first gas, the compressive forceand the pressure of the first gas are in equilibrium. Thus, first shockabsorber 20 a can maintain its cross-sectional elliptical shape withoutbeing deformed by compression components 71.

Here, as illustrated in (b) in FIG. 11, since the first gas is releasedvia release unit 26 when the gas release control is performed, thepressure of first gas and the compressive force from compressioncomponents 71 fall out of equilibrium. Accordingly, compressioncomponents 71 exert a compressive force that pulls the upper portion andlower portion of first shock absorber 20 a toward one another. As aresult, compression components 71 causes first gas chamber 21 a tocontract. This releases the first gas contained in the first gas chamber21 a more quickly. Thus, by performing the gas release control, aircraft10B can be caused to descend more quickly.

Variation 3

In aircraft 10 according to Embodiment 1, first shock absorber 20 a,20Aa is made of the same vinyl chloride as second shock absorber 20 b,but may be made of a material that is more fragile than vinyl chloride(for example, latex).

Variation 4

In aircraft 10 according to Embodiment 1, second shock absorber 20 b isthe portion of balloon 20 that defines second gas chamber 21 b, butsecond shock absorber 20 b is not limited to this example. For example,second shock absorber 20 b may be made of a solid material, such as asponge material or rubber material. In other words, second shockabsorber 20 b may be made of any material so long as the material canabsorb the impact when colliding with an object.

Variation 5

In aircraft 10 according to Embodiment 1, ventilation holes 22 in whichthe plurality of rotor units 30 are disposed each extend across firstshock absorber 20 a and second shock absorber 20 b, but ventilationholes 22 are not limited to this example. For example, the ventilationholes may be formed exclusively in the second shock absorber. Note thatwhen the ventilation holes are formed exclusively in the second shockabsorber, the first shock absorber may be small in size and disposedmore centrally than the ventilation holes. Moreover, a plurality of thefirst shock absorbers may be disposed in regions so as to avoid theupper and lower areas of the ventilation holes.

Variation 6

In Embodiment 1, the release instruction signal is received by receiver41 a included in controller 41, but this is merely one example. Therelease instruction signal may be received by a receiver included in adifferent controller independent from controller 41. In such cases, thedifferent controller is preferably supplied with power from a differentbattery than battery 42. In other words, the different receiver may beincluded in a controller in an auxiliary control system different fromthe control system including controller 41. Accordingly, even whencontroller 41, battery 42, etc., in the main control system malfunction,the operator can still operate a control terminal to control releaseunit 26. With this, even when the main control system malfunctions andcan no longer perform control, since the auxiliary control system can beused to control release unit 26, the first gas contained in first shockabsorber 20 a can be released to cause aircraft 10 to quickly descend.

Embodiment 2

Next, Embodiment 2 will be described.

Embodiment 2 is implemented to solve problems that arise when aircraft10 falls from the air. One example of aircraft 10 falling from the airis illustrated in FIG. 12, in which aircraft 10 falls to ground 100 whenthe gas release control described in Embodiment 1 is performed. Anotherexample of a cause of the aircraft falling from the air is when thegross weight of the aircraft is slightly greater than its buoyant forceand, for example, the aircraft encounters an unexpected flightsituation, such as one or more of rotor units 30 becominguncontrollable. Note that FIG. 12 illustrates aircraft 10 according toEmbodiment 1 having fallen to ground 100 as a result of the gas releasecontrol being performed.

(Configuration of Holding Components)

Since aircraft 10 according to Embodiment 2 is the same as aircraft 10according to Embodiment 1, detailed description thereof will be omitted.Here, the two holding components 54 included in fixing component 50whose functions were not described in detail in Embodiment 1 will bedescribed with reference to FIG. 13.

FIG. 13 is an enlarged view of holding components 54 and camera 44 inaircraft 10. In FIG. 13, (a) illustrates an enlarged view of holdingcomponents 54 and camera 44 when aircraft 10 is flying. In FIG. 13, (b)illustrates an enlarged view of holding components 54 and camera 44 whenaircraft 10 has fallen to ground 100.

As illustrated in (a) in FIG. 13, holding components 54 hold disc 40,which supports camera 44, in a state in which camera 44 is protrudingdownward. For example, when aircraft 10 is flying, holding components 54hold disc 40, which supports camera 44, at the bottom end of recess 29,and each have an overall length of first length L1. In other words, whenaircraft 10 is flying, holding components 54 hold camera 44 so as toprotrude downward, below balloon 20, thereby inhibiting balloon 20 fromentering the frame of the video being captured by camera 44 and makingit possible to capture video having a wide field of view.

As illustrated in (b) in FIG. 13, the overall length of each holdingcomponent 54 can be shortened along a predetermined axis extending upand down, i.e., the axis along which camera 44 protrudes from balloon20. More specifically, the overall length of each holding component 54can be shortened to a position at which camera 44 is housed in recess29. In other words, when disc 40 is in a position at which camera 44 ishoused in recess 29, the overall length of each holding component 54 issecond length L2. Holding components 54 are flexible, which allows themto contract and expand up and down. When camera 44 is pushed up frombelow, along the predetermined axis, holding components 54 contract.

For example, as illustrated in FIG. 13, holding components 54 may beimplemented as sliding rails each having three sections and capable ofsliding up and down. The three sections in each holding component 54 arecapable sliding along one another, and may have ball bearings to helpthem slide smoothly. Note that each holding component 54 may be asliding rail having two or four or more sections.

Since holding components 54 are capable of contracting, even when camera44 contacts ground 100, camera 44 can be housed in recess 29 of balloon20, reducing the impact imparted on camera 44.

Advantageous Effects, Etc., of Embodiment 2

Aircraft 10 according to this embodiment includes: a plurality of rotorunits 30 each of which includes propeller 32 and motor 33 that drivespropeller 32; balloon 20 functioning as a shock absorber that laterallycovers the plurality of rotor units 30, across a height of the pluralityof rotor units 30 in an up-and-down direction; camera 44 disposedprotruding downward, along a predetermined axis, beyond balloon 20; andholding components 54 that hold camera 44 and whose overall lengths canbe shortened in the up-and-down direction.

Accordingly, even when aircraft 10 accidentally contacts an object,camera 44, which is an on-board device, can recede into balloon 20. Thisreduces the impact imparted on camera 44 of aircraft 10 and/or theobject, and reduces damage to camera 44 and/or the object.

Moreover, in this embodiment, balloon 20 includes recess 29 of a sizecapable of housing camera 44, and the overall length of each holdingcomponent 54 can be shortened to a position at which camera 44 is housedin recess 29. Accordingly, even when aircraft 10 accidentally contactsan object, camera 44, which is an on-board device, can recede intorecess 29 of balloon 20. In other words, even if aircraft 10 contacts anobject, if holding components 54 contract to the position at whichcamera 44 is housed in recess 29, balloon 20 will contact the object inareas around recess 29, so the impact imparted to camera 44 and/or theobject can be effectively reduced.

Moreover, in this embodiment, holding components 54 are flexible, andwhen the camera is pushed up from below, contract. Accordingly, evenwhen camera 44 of aircraft 10 accidentally contacts an object, camera 44is pushed thereby causing holding components 54 to contract and camera44 to recede so as to be housed in recess 29 of balloon 20. In otherwords, even if camera 44 of aircraft 10 contacts an object, camera 44will resultantly be housed in recess 29 of balloon 20, and the nextthing that will contact the object is the bottom end of recess 29 ofballoon 20. This effectively reduces the impact imparted to camera 44and/or the object.

Variations of Embodiment 2

Variation 1

In Embodiment 2, holding components 54 are implemented as sliding rails,but holding components 54 are not limited to this example. For example,as illustrated in FIG. 14, holding components 54A implemented as bellowsmay be used. FIG. 14 is an enlarged view of holding components 54A andcamera 44 in the aircraft according to Variation 1 of Embodiment 2.

Moreover, the holding components are not limited to sliding rails orbellows; a configuration in which one of two sleeves having differentdiameters is inserted into the other may be used, and a configurationusing three or more metal wires, strings, or cords may be used.

Variation 2

In Embodiment 2, holding components 54 passively contract when camera 44is pushed up from below, but holding components 54 are not limited tothis example. For example, holding components 54 may be configured todetect when camera 44 is about to contact an object and activelycontract.

FIG. 15 is a block diagram illustrating a configuration of aircraft 10Caccording to Variation 2 of Embodiment 2. FIG. 16A is a flow chart ofone example of contraction control for holding components 54B inaircraft 10C according to Variation 2 of Embodiment 2. FIG. 16B is aflow chart of one example of contraction control for holding components54B in aircraft 10C according to Variation 2 of Embodiment 2. FIG. 17 isan enlarged view of holding components 54B and camera 44 in aircraft10C.

Aircraft 10C according to Variation 2 of Embodiment 2 differs fromaircraft 10 according to Embodiment 1 in that release unit 26 is omittedand replaced with holding components 54B driven by controller 41, asillustrated in FIG. 15. Moreover, what is detected by detector 81 inaircraft 10C according to Variation 2 of Embodiment 2 differs from whatis detected by the detector in aircraft 10 according to Embodiment 1.The remaining components in aircraft 10C according to Variation 2 ofEmbodiment 2 are the same as in aircraft 10 according to Embodiment 1.Accordingly, the following description will focus on the points ofdifference with aircraft 10 according to Embodiment 1; description ofother components is omitted.

Holding components 54B are implemented as, for example, electriccylinders whose overall lengths are adjusted via a motor. Note thatholding components 54B are not limited to electric cylinders, and may beimplemented as, for example, hydraulic or pneumatic cylinders. Theoverall length of each holding component 54B is shortened by holdingcomponents 54B being driven by controller 41 at a predetermined timing.

Detector 81 detects the state of aircraft 10C, and transmits apredetermined signal indicating a result of the detection to controller41. More specifically, detector 81 is implemented as a distancemeasuring unit configured to measure a distance to an object belowaircraft 10C. Detector 81 may be implemented as, for example, a rangingdevice capable of detecting the presence of an object within apredetermined distance by reflecting laser light or sound waves off anobject. For example, detector 81 may analyze image data captured bycamera 44 included in aircraft 10C to detect an object present in thesurrounding area of aircraft 10C.

In this way, by using detector 81 which uses laser light, sound waves,or image data, aircraft 10C can recognize an object relatively far away(for example, tens of meters) from aircraft 10C. Detector 81 istriggered to transmit the predetermined signal indicating the result ofthe detection to controller 41 when the object comes within apredetermined distance (for example, a few meters) from aircraft 10C.

Note that when detector 81 uses image data captured by camera 44, camera44 may function as detector 81.

In aircraft 10C having the configuration described above, thecontraction control may be implemented via, for example, the informationprocessing and operations illustrated in FIG. 16A. In other words,detector 81 detects the state of aircraft 10C (S21). Controller 41shortens the overall length of each holding component 54B in accordancewith the detection result from detector 81 (S22). In other words, withthe contraction control illustrated in FIG. 16A, controller 41 shortensthe overall length of each holding component 54B when, as thepredetermined timing, the distance to the object detected by detector 81is less than a predetermined distance.

In aircraft 10C having the configuration described above, thecontraction control may be implemented via, for example, the informationprocessing and operations illustrated in FIG. 16B. In other words,receiver 41 a receives a contraction instruction signal transmitted fromthe radio control device (S21 a). Controller 41 shortens the overalllength of each holding component 54B when, as the predetermined timing,receiver 41 a receives the contraction instruction signal (S22). Inother words, with the contraction control illustrated in FIG. 16B,controller 41 shortens the overall length of each holding component 54Bwhen, as the predetermined timing, receiver 41 a receives a contractioninstruction signal instructing that the overall length of each holdingcomponent 54B be shortened.

As a result of the contraction control described in FIG. 16A and FIG.16B, the overall length of each holding component 54B shortens fromfirst length L1 to second length L2, as illustrated in FIG. 17. Thismakes it possible to house camera 44 in recess 29 of balloon 20 at apredetermined timing.

In this way, for example, controller 41 can automatically shorten theoverall length of each holding component 54B when, as the predeterminedtiming, the distance to an object below aircraft 10C is less than apredetermined distance. With this, when aircraft 10C contacts an object,an on-board device, such as camera 44, can be housed within balloon 20so as not to protrude beyond balloon 20. This makes it possible toinhibit an on-board device from contacting an object and prevent damageto the on-board device and/or the object.

Moreover, for example, controller 41 can shorten the overall length ofholding components 54B as a result of the operator using the radiocontrol device to transmit a contraction instruction signal. With this,as a result of the operator shortening the overall length of holdingcomponents 54B at a predetermined timing, an on-board device can behoused within balloon 20 so as not to protrude beyond balloon 20, evenwhen aircraft 10C is flying. This makes it possible to inhibit anon-board device from contacting an object and prevent damage to theon-board device and/or the object.

In FIG. 17, each holding components 54B is implemented as a cylinderdevice such as an electric cylinder, but holding components 54B are notlimited to cylinder devices. For example, as illustrated in FIG. 18, theholding components may be implemented as holding component 54C having astructure including a plurality of links each supportably rotatable atthree axes of rotation. Even with the structure of holding component54C, the overall length of holding component 54C can be shortened.

Moreover, the overall lengths of holding components 54B, 54C areshortened at a predetermined timing. Thereafter, holding components 54B,54C may be extended at a different timing. In other words, holdingcomponents 54B, 54C are variable-length components capable ofcontracting and extending. For example, receiver 41 a receives alength-change instruction signal (contraction instruction signal orextension instruction signal) transmitted from the radio control device.Controller 41 changes (extends or shortens) the overall length ofholding components 54B, 54C when, as the predetermined timing, receiver41 a receives the length-change instruction signal.

Variation 3

In Embodiment 2 described above, aircraft 10 has, but it not limited to,the same configuration as described in Embodiment 1; for example,release unit 26 may be omitted from aircraft 10. Moreover, balloon 20 isexemplified as gas chamber 21 being divided into first shock absorber 20a and second shock absorber 20 b, but balloon 20 may have a single gaschamber. In such cases, balloon 20 preferably contains the same gas asthe first gas. Moreover, in Embodiment 1, at least the first shockabsorber is required to be a balloon, but this example is not limiting;so long as the shock absorber laterally covers the plurality of rotorunits 30, across the height of the plurality of rotor units 30 in theup-and-down direction, the shock absorber may be made of any material.In other words, in Embodiment 2, the shock absorber may be made of asolid material such as a sponge material or rubber material.

Embodiment 3

Next, Embodiment 3 will be described.

Embodiment 3 is implemented mainly to solve problems that arise when theaircraft falls from the air, similar to Embodiment 2. As cases in whichthe aircraft falls from the air are described in Embodiment 2, repeateddescription thereof will be omitted.

FIG. 19 illustrates aircraft 10D according to Embodiment 3 whenshape-change control is performed. Note that (a) in FIG. 19 illustratesaircraft 10D before the shape-change control is performed, andcorresponds to the cross section as illustrated in FIG. 3. Note that (b)in FIG. 19 illustrates the overall state of aircraft 10D after theshape-change control has been performed.

Aircraft 10D according to Embodiment 3 differs from the aircraftaccording to Embodiment 1 in regard to the configuration of fixingcomponent 50C, as illustrated in FIG. 19. As such, fixing component 50Cwill be described.

Fixing component 50C differs from fixing component 50 in aircraft 10according to Embodiment 1 in that arms 52C are capable of contracting.

The plurality of arms 52C each include movable part 52 b includingdistal end section 52 a, and fixed part 52 c. The plurality of arms 52Ceach contract by housing movable part 52 b inside fixed part 52 c. Theplurality of arms 52C are configured as, for example electric cylinders.In each arm 52C, the portion of movable part 52 b that is exposed inventilation hole 22 is fixed to ventilation hole 22. Accordingly, as aresult of each of the plurality of arms 52C contracting, the externalshape of balloon 20 changes, as illustrated in (b) in FIG. 19. Morespecifically, the shape of balloon 20 having a height H1 and a width W1before the plurality of arms 52C are contracted changes to a shape inwhich the width of balloon 20 narrows, to a width W2 smaller than widthW1, when the plurality of arms 52C contract. The pressure inside balloon20 causes the height of balloon 20 to increase by the amount by whichthe width of balloon 20 narrows, to a height of H2 greater than heightH1.

This causes the bottom end of recess 29 of balloon 20 to lower inposition, whereby an on-board device, such as camera 44, is housedinside recess 29.

In other words, the plurality of arms 52C of fixing component 50C aredriven by drive unit 90 (to be referenced later) and change the externalshape of balloon 20 functioning as the shock absorber at a predeterminedtiming. More specifically, the plurality of arms 52C change the externalshape of balloon 20 so that part or all of an on-board device, such ascamera 44, does not protrude beyond balloon 20. The plurality of arms52C are connected to ventilation holes 22 in four locations insideballoon 20, and change the external shape of balloon 20 by pullingventilation holes 22 closer together.

With this, the plurality of arms 52C cause recess 29, which defines atleast part of the external shape of balloon 20, to protrude downward.Even more specifically, the plurality of arms 52C cause at least part ofballoon 20 in the surrounding area of camera 44 to protrude beyondcamera 44.

Note that all four of the plurality of arms 52C contract, but by causingonly the two arms 52C that contract in opposite directions to contract,two locations inside balloon 20 can be brought closer to each other.Accordingly, the configuration is not limited to four arms being capableof contracting; two arms that contract in opposite directions may becapable of contracting.

(Aircraft Operation Control Example)

With aircraft 10D according to this embodiment, shape-change control isperformed at a predetermined timing to change the external shape ofballoon 20.

Next, this shape-change control according to aircraft 10D will bedescribed with reference to FIG. 19 through FIG. 21B.

FIG. 20 is a block diagram illustrating a configuration of aircraft 10Daccording to Embodiment 3. FIG. 21A is a flow chart of one example ofthe shape-change control performed by drive unit 90 in aircraft 10Daccording to Embodiment 3. FIG. 21B is a flow chart of another exampleof the shape-change control performed by drive unit 90 in aircraft 10Daccording to Embodiment 3.

Aircraft 10D according to Embodiment 3 differs from aircraft 10Caccording to Variation 2 of Embodiment 2 in that it includes arms 52Cinstead of holding components 54B. The remaining components in aircraft10D according to Embodiment 3 are the same as in aircraft 10 accordingto Embodiment 1.

Controller 41 contracts the plurality of arms 52C at a predeterminedtiming. Drive unit 90 changes the external shape of balloon 20 as aresult of the plurality of arms 52C contracting.

In aircraft 10D having the configuration described above, theshape-change control may be implemented via, for example, theinformation processing and operations illustrated in FIG. 21A. In otherwords, detector 81 detects the state of aircraft 10D (S31). Controller41 changes the external shape of balloon 20 in accordance with theresult of the detection by detector 81 (S32). In other words, with theshape-change control illustrated in FIG. 21A, controller 41 changes theexternal shape of balloon 20 when, as the predetermined timing, thedistance detected by detector 81 is less than a predetermined distance.

In aircraft 10D having the configuration described above, theshape-change control may be implemented via, for example, theinformation processing and operations illustrated in FIG. 21B. In otherwords, receiver 41 a receives a shape-change instruction signaltransmitted from the radio control device (S31 a). Controller 41 changesthe external shape of balloon 20 when, as the predetermined timing,receiver 41 a receives the shape-change instruction signal (S32). Inother words, in the shape-change control illustrated in FIG. 21B,controller 41 changes the external shape of balloon 20 when, as thepredetermined timing, receiver 41 a receives the shape-changeinstruction signal, which instructs the changing of the external shapeof balloon 20.

As a result of the shape-change control described with reference to FIG.21A and FIG. 21B being performed, the plurality of arms 52C contract,which causes the external shape of balloon 20 to change, as illustratedin FIG. 19. This makes it possible to house camera 44 in recess 29 ofballoon 20 at a predetermined timing.

(Advantageous Effects, Etc., of Embodiment 3)

Aircraft 10D according to this embodiment includes: a plurality of rotorunits 30 each including propeller 32 and motor 33 that drives propeller32; balloon 20 that laterally covers the plurality of rotor units 30,across a height of the plurality of rotor units 30 in an up-and-downdirection; and a plurality of arms 52C that are driven by drive unit 90to change the external shape of balloon 20 at a predetermined timing.

With this configuration, since the external shape of balloon 20 can bechanged at a predetermined timing, when, for example, aircraft 10Dencounters an unexpected flight situation, the external shape of balloon20 can be changed such that an on-board device, such as camera 44, doesnot protrude beyond balloon 20, making it possible to inhibit theon-board device(s) from impacting an object. Moreover, for example, bychanging the external shape of external shape balloon 20 of aircraft10D, aircraft 10D can be used for entertainment purposes.

In this embodiment, aircraft 10D further includes camera 44 thatprotrudes beyond balloon 20, and drive unit 90 changes the externalshape of balloon 20 such that a part or all of camera 44 does notprotrude beyond balloon 20. In other words, when, for example, aircraft10D encounters an unexpected flight situation, the external shape ofballoon 20 can be changed such that camera 44, which is protrudingbeyond balloon 20, no longer protrudes beyond balloon 20. As such, evenif aircraft 10D contacts an object, camera 44 can be effectivelyinhibited from directly contacting the object. Accordingly, even ifaircraft 10D, for example, encounters an unexpected flight situation andcontacts an object, camera 44 and/or the object can be prevented frombeing damaged.

In this embodiment, drive unit 90 changes the external shape of balloon20 by causing at least part of the external shape of balloon 20 toprotrude beyond camera 44. In other words, when, for example, aircraft10D encounters an unexpected flight situation, the external shape ofballoon 20 can be changed such that camera 44, which is protrudingbeyond balloon 20, no longer protrudes beyond a part of balloon 20. Assuch, even if aircraft 10D contacts an object, balloon 20 will contactthe object before camera 44 does. Accordingly, even if aircraft 10D, forexample, encounters an unexpected flight situation and contacts anobject, camera 44 can be prevented from being damaged.

In this embodiment, drive unit 90 changes the external shape of balloon20 by causing at least part of balloon 20, in a surrounding area ofcamera 44, to protrude beyond camera 44. In other words, when, forexample, aircraft 10D encounters an unexpected flight situation, theexternal shape of balloon 20, in an area surrounding an on-board device,such as camera 44, can be changed such that the on-board device does notprotrude beyond a part of balloon 20. As such, even if aircraft 10Dcontacts an object in any sort of orientation, balloon 20 will contactthe object before the on-board device does. Accordingly, even ifaircraft 10D, for example, encounters an unexpected flight situation andcontacts an object, the on-board device and/or object can be preventedfrom being damaged.

In this embodiment, aircraft 10D further includes detector 81functioning as the distance measuring unit that measures the distance toan object below aircraft 10D. Moreover, the predetermined timing is whenthe distance measured by detector 81 is less than a predetermineddistance. Furthermore, drive unit 90 changes the external shape ofballoon 20 when the distance measured by detector 81 is less than thepredetermined distance.

In this way, controller 41 can automatically contract the plurality ofarms 52C when, as the predetermined timing, the distance to an objectbelow aircraft 10D is less than the predetermined distance. With this,when aircraft 10D contacts an object, an on-board device, such as camera44, can be housed within balloon 20 so as not to protrude beyond balloon20, since it is possible to change the external shape of balloon 20 toits post-change form. This makes it possible to inhibit an on-boarddevice from contacting an object and prevent damage to the on-boarddevice and/or the object.

In this embodiment, aircraft 10D further includes receiver 41 a thatreceives a signal. Moreover, the predetermined timing is when receiver41 a receives a shape-change instruction signal, which instructs thechanging of the external shape of balloon 20. Furthermore, the pluralityof arms 52C change the external shape of balloon 20 when receiver 41 areceives the shape-change instruction signal.

As such, for example, controller 41 can contract the plurality of arms52C as a result of the operator using the radio control device totransmit the shape-change instruction signal. With this, as a result ofthe operator shortening the overall length of the plurality of arms 52Cat a predetermined timing, an on-board device can be housed withinballoon 20 so as not to protrude beyond balloon 20, even when aircraft10D is flying. This makes it possible to inhibit an on-board device fromcontacting an object and prevent damage to the on-board device and/orthe object.

The overall lengths of the plurality of arms 52C are shortened at apredetermined timing. Thereafter, the plurality of arms 52C may beextended at a different timing. In other words, the plurality of arms52C are variable-length components capable of contracting and extending.The plurality of arms 52C are connected to ventilation holes 22 in fourlocations inside balloon 20, and change the external shape of balloon 20by pulling ventilation holes 22 closer together or pushing them fartherapart.

Variations of Embodiment 3

Variation 1

In aircraft 10D according to Embodiment 3 described above, drive unit 90is exemplified as, but not limited to, changing the external shape ofballoon 20 by contracting the plurality of arms 52C included in fixingcomponent 50C; for example, the configuration illustrated in FIG. 22 maybe implemented.

FIG. 22 illustrates aircraft 10E according to Variation 1 of Embodiment3 when shape-change control is performed. Note that (a) in FIG. 22illustrates aircraft 10E before the shape-change control is performed,and corresponds to the cross section as illustrated in FIG. 3. Note that(b) in FIG. 22 illustrates the overall state of aircraft 10E after theshape-change control has been performed.

Aircraft 10E according to Variation 1 of Embodiment 3 differs fromaircraft 10D according to Embodiment 3 in that it includes externalshape changing unit 72, as illustrated in FIG. 22.

External shape changing unit 72 includes connectors 72 a, string-likecomponents 72 b, and recessed region 72 c in which part of the externalshape of balloon 20E is recessed.

Connectors 72 a are located in the central region of the inside ofballoon 20E. Each connector 72 a is connected to one end of astring-like component 72 b. Connectors 72 a severs one end of eachstring-like component 72 b by disconnecting string-like components 72 bupon being driven by drive unit 90 having received a shape-changecommand from controller 41.

String-like components 72 b each have one end connected to a connector72 a and the other end connected to the part of balloon 20Ecorresponding to the base of recessed region 72 c. In other words, theshape of recessed region 72 c is maintained by string-like components 72b connecting the base of recessed region 72 c to another part of balloon20E, inside balloon 20E, via connectors 72 a.

In aircraft 10E configured in this manner, drive unit 90 disconnectsconnectors 72 a at a predetermined timing to cause recessed region 72 cto protrude beyond camera 44 via the internal pressure of balloon 20E,as illustrated in (b) in FIG. 22. This causes recess 29 of balloon 20Eto protrude from an area surrounding camera 44 to form recess 29E thatsurrounds the entire perimeter of camera 44. Accordingly, with a simpleconfiguration, part of balloon 20E can be caused to protrude beyond anon-board device, such as camera 44, at a predetermined timing.

Variation 2

For example, instead of the configuration described in Variation 1, theconfiguration illustrated in FIG. 23 may be implemented.

FIG. 23 illustrates aircraft 10F according to Variation 2 of Embodiment3 when shape-change control is performed. Note that (a) in FIG. 23illustrates aircraft 10F before the shape-change control is performed,and corresponds to the cross section as illustrated in FIG. 3. Note that(b) in FIG. 23 illustrates the overall state of aircraft 10F after theshape-change control has been performed.

Aircraft 10F according to Variation 2 of Embodiment 3 differs in that itincludes gas supply unit 73, as illustrated in FIG. 23. Aircraft 10Falso differs in that balloon 20F includes first region 75 that isinflated and second region 74 that is deflated.

Gas supply unit 73 is capable of supplying gas to second region 74. Morespecifically, gas supply unit 73 is a valve that is disposed betweenfirst region 75 and second region 74 and selectively places first space75 a defined by first region 75 in fluid communication with second space74 a that second region 74 is capable of defining.

Drive unit 90 supplies gas contained in first space 75 a to secondregion 74 by opening gas supply unit 73 at a predetermined timing. Inother words, at a predetermined timing, drive unit 90 causes gas supplyunit 73 to inflate second region 74 by supplying gas to second region74, which causes second region 74 to protrude from balloon 20F.

In aircraft 10F configured in this manner, at a predetermined timing,drive unit 90 opens gas supply unit 73 to cause second region 74 toprotrude beyond camera 44, using the gas filling balloon 20F, asillustrated in (b) in FIG. 23. This causes recess 29 of balloon 20F toprotrude from an area surrounding camera 44 to form recess 29F thatsurrounds the entire perimeter of camera 44. Accordingly, with a simpleconfiguration, part of balloon 20F can be caused to protrude beyond anon-board device at a predetermined timing.

Variation 3

In Variation 2, gas supply unit 73 is exemplified as a valve, but asillustrated in FIG. 24, may be implemented as gas supply unit 73Aconfigured as a canister filled with gas.

FIG. 24 illustrates aircraft 10G according to Variation 3 of Embodiment3 when shape-change control is performed. Note that (a) in FIG. 24illustrates aircraft 10G before the shape-change control is performed,and corresponds to the cross section as illustrated in FIG. 3. Note that(b) in FIG. 24 illustrates the overall state of aircraft 10G after theshape-change control has been performed.

Aircraft 10G according to Variation 3 of Embodiment 3 differs in that itincludes gas supply unit 73A instead of gas supply unit 73, asillustrated in FIG. 24.

Drive unit 90 supplies gas from gas supply unit 73A to second region 74at a predetermined timing. In other words, at a predetermined timing,drive unit 90 causes gas supply unit 73A to inflate second region 74 bysupplying gas to second region 74, which causes second region 74 toprotrude from balloon 20F.

In aircraft 10G configured in this manner, at a predetermined timing,drive unit 90 supplies gas filled in gas supply unit 73A to cause secondregion 74 to protrude beyond camera 44, as illustrated in (b) in FIG.24. This causes recess 29 of balloon 20F to protrude from an areasurrounding camera 44 to form recess 29F that surrounds the entireperimeter of camera 44. Accordingly, with a simple configuration, partof balloon 20F can be caused to protrude beyond an on-board device at apredetermined timing.

Variation 4

For example, instead of the configurations described in Variations 1through 4, the configuration illustrated in FIG. 25 may be implemented.

FIG. 25 illustrates aircraft 10H according to Variation 4 of Embodiment3 when shape-change control is performed. Note that (a) in FIG. 25illustrates aircraft 10H before the shape-change control is performed,and corresponds to the cross section as illustrated in FIG. 4. Note that(b) in FIG. 25 illustrates the overall state of aircraft 10H after theshape-change control has been performed.

Aircraft 10H according to Variation 4 of Embodiment 3 differs in that itincludes external shape changing unit 76, as illustrated in FIG. 25.

External shape changing unit 76 includes connectors 76 a, string-likecomponents 76 b, and protruding region 77 in which part of the externalshape of balloon 20H is protruding.

Connectors 76 a are located on the outer surface of balloon 20H. Eachconnector 76 a is connected to one end of a string-like component 76 b.Connectors 76 a each sever one end of a string-like component 76 b bydisconnecting string-like component 72 b upon being driven by drive unit90 having received a shape-change command from controller 41.

String-like components 76 b each have one end connected to a connector76 a and the other end connected to a distal end of protruding region 77of balloon 20H. With this, protruding region 77 has a distal end thatconnects to part of the outer surface of balloon 20H via connector 76 ato give protruding region 77 a shape that follows the contour of theouter surface of balloon 20H.

In aircraft 10H configured in this manner, drive unit 90 disconnectsconnectors 76 a at a predetermined timing to cause protruding region 77to protrude beyond camera 44 via the internal pressure of balloon 20H,as illustrated in (b) in FIG. 25. Accordingly, with a simpleconfiguration, part of balloon 20H can be caused to protrude beyond anon-board device, such as camera 44, at a predetermined timing.

Variation 5

In Embodiment 3 described above, the external shape of balloon 20 ischanged by contracting plurality of arms 52C, but this example is notlimiting. For example, cord-like components may be attached in twodifferent locations, and the cord-like components may be reeled in witha reel to bring the two different locations closer together. This makesit possible to change the external shape of balloon 20 with a simpleconfiguration.

Other Embodiments

The embodiments described above include fixing component 50, 50C, butfixing component 50, 50C may be omitted. In such cases, the plurality ofrotor units 30 are fixed directly to ventilation holes 22. Moreover, theballoon need not include the plurality of ducts 28.

The above embodiments have been presented as examples of techniquesaccording to the present disclosure. The accompanying drawings and thedetailed description are provided for this purpose.

Therefore, the components described in the accompanying drawings and thedetailed description include, in addition to components essential toovercoming problems, components that are not essential to overcomingproblems but are included in order to exemplify the techniques describedabove. Thus, those non-essential components should not be deemedessential due to the mere fact that they are illustrated in theaccompanying drawings and described in the detailed description.

The above embodiments are for providing examples of the techniquesaccording to the present disclosure, and thus various modifications,substitutions, additions, and omissions are possible in the scope of theclaims and equivalent scopes thereof.

INDUSTRIAL APPLICABILITY

The present disclosure is applicable to an aircraft including aplurality of rotor units and a shock absorber.

What is claimed is:
 1. An aircraft, comprising: a plurality of rotorunits each including a propeller and a motor that drives the propeller;a shock absorber that laterally covers the plurality of rotor units; acamera for capturing aerial video; a holding component that holds thecamera and is variable in overall length along an up-and-down axis; acontroller comprising a computer that changes the overall length of theholding component by driving the holding component; and a distancemeasuring unit configured to measure a distance to an object below theaircraft, wherein: the shock absorber includes a recess having a sizesuch that the recess houses the camera, the overall length of theholding component is variable to a first position at which the camera ishoused in the recess and a second position at which the camera protrudesbeyond the shock absorber along the up-and-down axis, and thecontroller: causes the distance measurement unit to measure thedistance, and shortens the overall length of the holding component whenthe holding component is in the second position and the distancemeasured by the distance measuring unit is less than a predetermineddistance, such that the camera is housed in the recess not to contactthe object.
 2. The aircraft according to claim 1, wherein the holdingcomponent is flexible, and when the camera is pushed along theup-and-down axis, contracts.
 3. The aircraft according to claim 1,further comprising: a receiver that receives a signal, wherein when theholding component is at the second position and the receiver receives alength-change instruction signal instructing that the overall length ofthe holding component be changed, the computer is further configured toshorten the overall length of the holding component so that the holdingcomponent is at the first position.
 4. The aircraft according to claim1, wherein the shock absorber laterally covers the plurality of rotorunits, across a height of the plurality of rotor units in theup-and-down axis.
 5. The aircraft according to claim 1, wherein theholding component includes a disc and a gimbal and the camera isattached to a bottom surface of the disc via the gimbal such that thecamera is angled diagonally with respect to the up-and-down axis.
 6. Anaircraft, comprising: a plurality of rotor units each including apropeller and a motor that drives the propeller; a shock absorber thatlaterally covers the plurality of rotor units; a camera for capturingaerial video an on-board device that protrudes, along a predeterminedaxis, beyond the shock absorber; a holding component that holds thecamera and is variable in overall length along the predetermined axis; adistance measuring unit configured to measure a distance to an objectbelow the aircraft; and a controller comprising a computer, wherein: theshock absorber includes a recess having a size such that the recesshouses the camera, the overall length of the holding component isvariable to a first position at which the camera is housed in the recessand a second position at which the camera protrudes beyond the shockabsorber along the downward axis, and the computer is programmed to:cause the distance measurement unit to measure the distance, and shortenthe overall length of the holding component, when the holding componentis at the second position and the distance measured by the distancemeasuring unit is less than a predetermined distance, such that thecamera is housed in the recess not to contact the object.
 7. Theaircraft according to claim 6, wherein the holding component isflexible, and when the camera is pushed along the up-and-down axis,contracts.
 8. The aircraft according to claim 6, further comprising: areceiver that receives a signal, wherein when the holding component isat the second position and the receiver receives a length-changeinstruction signal instructing that the overall length of the holdingcomponent be changed, the computer is further programmed to shorten theoverall length of the holding component so that the holding component isat the first position.
 9. The aircraft according to claim 6, wherein theshock absorber laterally covers the plurality of rotor units, across aheight of the plurality of rotor units in the up-and-down axis.
 10. Theaircraft according to claim 6, wherein the holding component includes adisc and a gimbal and the camera is attached to a bottom surface of thedisc via the gimbal such that the camera is angled diagonally withrespect to the downward axis.
 11. A method, comprising: providing anaircraft comprising: a plurality of rotor units each including apropeller and a motor that drives the propeller; a shock absorber thatlaterally covers the plurality of rotor units; a camera for capturingaerial video; a holding component that holds the camera and is variablein overall length along a downward axis; and a distance measuring unitconfigured to measure a distance to an object below the aircraft,wherein: the shock absorber includes a recess having a size such thatthe recess houses the camera, the overall length of the holdingcomponent is variable to a first position at which the camera is housedin the recess and a second position at which the camera protrudes beyondthe shock absorber along the downward axis; measuring the distance bythe distance measuring unit; and shortening the overall length of theholding component, when the holding component is in the second positionand the distance measured by the distance measuring unit is less than apredetermined distance, such that the camera is housed in the recess notto contact the object.
 12. The method according to claim 11, wherein theholding component is flexible, and when the camera is pushed along thedownward axis, contracts.
 13. The method according to claim 11, wherein,the method further comprises, when the holding component is at thesecond position and a length-change instruction signal instructing thatthe overall length of the holding component be changed is received bythe aircraft, shortening the overall length of the holding component sothat the holding component is at the first position.
 14. The methodaccording to claim 11, wherein the shock absorber laterally covers theplurality of rotor units, across a height of the plurality of rotorunits in the up-and-down axis.
 15. The method according to claim 11,wherein the holding component includes a disc and a gimbal and thecamera is attached to a bottom surface of the disc via the gimbal suchthat the camera is angled diagonally with respect to the downward axis.